An investigation of the pyrolysis kinetics of some aliphatic amino acids

The thermal behavior of some aliphatic amino acids, including alanine, valine, leucine, isoleucine, and proline was investigated by thermogravimetry (TG) in the range of temperatures within 30-400 degrees C. Pyrolysis of these amino acids was performed at various heating rates under inert (non-oxidative) conditions. The kinetic analysis was carried out using a composite procedure involving the iso-conversional method and the master plots method. The iso-conversional method indicated that the pyrolysis reaction should conform to single reaction model. The master plots method suggested that the phase boundary reaction models best describe the pyrolysis of alanine, valine, leucine and isoleucine, while the pyrolysis of proline should conform to the simple order reaction model. Also, for each amino acid, the kinetic parameters, such as activation energy and pre-exponential factor, were determined, respectively. (c) 2005 Elsevier B.V. All rights reserved.